Undertails
by DrCr0ss0ver
Summary: [ON HIATUS, possibly discontinued] 6 months after Sonic X, season 3. Team Sonic return to Earth after Eggman's total takeover of Mobius. One month after arriving, Tails is shot down, injured and falls into a hole rumored to be filled with monsters. Can Tails survive the monsters below? How will Sonic react? Rate T for: violence, minor swearing, and others.
1. Chapter 1: Beginnings

Hi all! Before this starts, I need to give you guys a few warnings/notes!

First! This is my first fanfiction, meaning that his is prone to have a few errors. Please do not be afraid to express how you feel about this story to me, as I could use all the help I can get to be better!

Second! This chapter takes place 6 months after season 3 of Sonic X.

Third! Please tell me if the cover page(not the title) is messed up for you, I had trouble making it work. With that, I think that is everything! Please enjoy this story!

Edit: ok, so I looked at the views betwwen the chapters, and there is a huge amount of difference between chapters 1 and 2. If you don't like chapter 1 or 2, skip to chapter 3, the real plotline begins (in a sense) there...

* * *

It has been 6 months after Chris was shuttled back to earth by Eggman and many events have occurred on Mobius during that amount of time. Eggman's attacks have grown more strategic and more intense than ever. Most of the city's on the planet are destroyed or captured by Eggman's forces. Much of the resistance has been wiped out, or have evacuated with the remaining survivors to a nearby moon.

Team Sonic have also been busy dealing with Eggman's upgraded forces, forcing them to adapt and live a little more secretive than normal. However, as of last 2 months, Eggman has gone dark with no sign of any activity. During this time, the team sought this as a break from battling Eggman, as they surely did need this time to relax and become more prepared to fight him if he returns.

Within a nearby forest, laid Sonic, who was lying down under a tree for sleep. It has been a time of peace, but he kept himself on alert just in case if Eggman made a sudden attack. Chuckling to himself, Sonic stretched his arms out and got up to do a daily run.

Before he took off at his immense speeds, a thought faster than himself came into his mind. Tails. Sonic knew he was still struggling with the death of Cosmo, the one he loved so much. It has hurt him so much he refused to anything; be with friends, he rarely talked to anyone, staying in his hut to be by himself, nothing! Tails would just lock himself away and cry to himself for the whole days worth, sometimes Sonic himself would hear his cries of pain. Looking behind him, he caught a tiny glimpse of his and Tail's huts from behind a line of trees. An idea popped into his head that made him nearly smack himself for not doing it earlier: make Tails chili dogs in the way he always loved! Besides, there was something grave that he must tell him.

Sonic smiled at himself for coming up with a brilliant idea. Rushing back to his hut, he quickly dashed into his kitchen to open a cabinet. Inside contained the recipes for everything that he made in the past: chili dog recipes, cake mixes, etc; Sonic was frantically throwing papers left and right to find the one which contained to ingredients to make Tail's favorites.

"No, not here. Nope. No not this one. No. NO. NO!" Sonic said to himself while rustling with all the papers until he finally found a slightly crumpled paper that read: Tail's Chili Dog Recipe. Sonic nearly Jumped for joy as he read the paper to find all he needed. As soon as he finished, Sonic turned around, only to see the mess that he has caused in his small kitchen.

"Heheh… well, my place is a mess now. Just hope Amy doesn't see this" Sonic chuckled to himself as he rushed all around his cabinets to find all the ingredients. After managing to get all of them, Sonic frantically worked to make and prepare a ton of dogs to hopefully make Tails give an actual smile. Sonic made an evil grin as he cooked up his perfection of a meal.

* * *

 _Meanwhile_

In his room, Tails was crying, no, bawling his eyes out. Even after Six months he cannot keep Cosmo out of his mind for even a millisecond. He will always have to go on while knowing that he had to sacrifice her in order to save the universe… no… he _killed_ her… he _killed_ the one he loved so much… to save the universe. It always scarred him, and will remain that way. Tails eyes, were completely read from crying so much, it hurt to even sleep.

He wanted to just sink away from everything, to where he would be in the way of everyone so that they wouldn't have to worry about him. He wanted to see her again, his love… his joy… his happiness. Looking up to his window, Tails looked at his potted plant. Inside was a seed containing the last remnant of Cosmo; the one that Sonic gave him after the battle with Dark Oak. He will never forget that look on Sonic's face, he will never-

Interrupting his thoughts was 3 loud knocks coming from his front door. Startled by the recent interruption, Tails slowly walked over to front door without making a sound to hear,"-ils, bud? Hello? You There? … look, I'm not leaving until you answer, and you know that right?"

Tails gave a small, aggravated sigh. Sonic was here again with his- wait, what is that smell? As if Sonic read his mind, he gave a reply," Yeah, I made your favorite kind of chili dogs!" Before Tails could tell him to leave, a small rumble escaped his belly. Tails gave a small, teary chuckle before opening the door to his brother.

"There you are! Welcome back!" Sonic exclaim as if he had never seen him in 4 years. Tails rolled his tear-dried eyes and let his brother in. He eyed the chili dogs as they entered his hut, giving a small grin and tongue sticking out. He was hungry, whether he could deny it or not. In any case, Tails followed Sonic to his kitchen, where Sonic placed the mountainous plate of chili dogs on a table.

The two sat down and began to eat the monstrous pile of chili dogs down, making general small talk along the way. A few small giggles escaped the fox every now and then while Sonic recalled his fancy acts of heroism. However toward the end of the meal, Sonic began to look a little more serious than earlier. Tails noticed this and commented on why Sonic looked the way he is. Sonic stopped eating a chili dog, swallowed the last bit of it before replying," Tails… we need to talk."

"I-if this i-is about Cosmo, t-then just l-leave," Tails barely managed to get that out of his raspy, crying voice.

Sonic shook his head,"no, that's not it. I need to talk to you about the future." Tails gave a puzzling look," the future?"

Sonic nodded before standing up," Tails, you know how you wanted to fix up the Blue Typhoon for a just in case?" Tails gave a slight nod and a sniffle. It was just that, he wanted to leave everything behind so he could start all over, that was just a cover story. Sonic continued," you also know how Eggman has been adapting to us and his overall armies, right?" Tails nodded again.

"Listen… I know this will come as a shocker, but the team and I cam to a conclusion. With the recent turn of events, the fact that civilians are leaving the planet, and the resistance's… demise… it's clear that…" Sonic looked down, making Tails slightly worried, but what Sonic said next would shock him beyond imagination,"It is safe to say… we must abandon Mobius."

Tails jaw dropped,"w-what? B-but this is o-our h-home! W-we can't just leave" Tails cried out.

"I know… but, Mobius isn't what it was years ago, and never will be again. Eggman has become such a problem, to a point where even if we did stop him, there would be no way of undoing the damage he has caused. So why not just give him the planet?" Sonic said, still looking down.

"B-because it's our h-home!" Tails retaliated.

"Tails, please, listen. Eggman has been off the grid for 2 months, and if that continues, we might have a chance to leave." Sonic stated. Tails saw the look in his eyes, they were scared, but were so very _determined_ as well. Tails knew when he had that look, there was no stopping him.

Tails gave a small sigh before saying,"when do we leave?"

"If all goes to plan, tomorrow."

"TOMORROW!" Tails nearly jumped out of his skin.

"I know this was sudden, believe me, I felt the same way; just please understand that we have no other options." Tails just put his head on his arms, muffled he replied,"where would we go?"

Sonic looked away in a heroic like stance, giving a small glace to his brother before saying with a small smile,"Earth."

* * *

 _Meanwhile on Earth_

Underneath the grounds of the Earth laid a civilization of monsters. Within there laid a small, happy town of Snowdin. Many of the residence were known for their generosity to each other, but there was one in particular who didn't care at all. Toward the back of the town in a old wooden house, a small skeleton was asleep on his messy bed. With a sudden jump, the small skeleton woke up with a gasp and heavy breathing. His left eye glowing an immense blue, while the right remained a soft white glow. Struggling to calm himself, the skeleton began to breathe slower in an attempt to relieve himself. He managed to control it's breathing before wiping the sweat off his head.

After a few minutes of controlled breathing, he heard the sound of boots walking toward him before 3 loud knocks, along with a voice greeted him.

"SANS! ARE YOU UP YET?" the voice behind the door yelled. The small skeleton, Sans, manage to cease his left eye's glow before replying,"yeah bro, i'm awake."

"SPLENDID! NOW HURRY UP AND GET READY! BREAKFAST IS ON THE COUNTER! NYEH HEH HEH HEH!" the voice cackled before walking off. Sans managed to get off this mattress, grab his blue jacket, white shirt, shorts, and slippers before walking to the door.

"yeah, papyrus. it's not like i'm ready to see you die again for the 43rd time in a row or anything" Sans muttered to himself before opening the door. Halfway through the door frame, Sans cupped his left hand under his chest. A white, upside down, slightly cracked heart appeared in front of him. Sans looked at his his hp: 1/1, looks like he was alright for now.

Sans scowled to himself saying,"alright kid, let see what kinda run were doing today," before closing the door behind him.

* * *

AN: WHOO! First chapter done! Like I said before, let me know of anything that I need to work on!

Also, the main crossover might not happen until at least chp 3-5, so just a heads up for the future! This next chapter or two might be just background story so I can fill you in on the plot and how it goes!


	2. Chapter 2: Warm Welcomes

Um, hey! So! I know the last chapter was... Iffy and kinda crappy; I get it, I suck at writing. Yeah, but I am trying my best to strive for perfection [even though that really isn't possible since were human ;) ].

Also! That last chapter was a bit too short IMO, so i'm gonna take more time to make them more lengthy, however, they will not become miniature phonebooks.

Plus I wasn't able to get that dang cover fixed so at the moment it's out of commission. If anyone has a way to make it work please let me know! Thx.

Anyway! Hopefully I can make this series a little more enjoyable for you readers, and without further delay… CHAPTER 2! AND HAPPY NEW YEARS!

* * *

 _Tails' shack, in the kitchen still_

Tails couldn't believe it, Earth. They were going back to Earth. He could see Chris again! He always dreamed of returning back to Earth to see any new marvels in human technology now they had the knowledge of Eggman's forces… wait, EGGMAN!

"Sonic! What about Eggman! Wouldn't he have notice we had left?" Tails asked in a concerned voice. Sonic shook his head.

"No, and besides: you know he's gone dark for 2 months now right?" Sonic returned Tails question with his.

"*sigh*Yeah, I guess that's true. And, what of the others? Do they-" Tails was cut off by Sonic (as usual)

"Know? Yeah, everyone is already packed and ready to go. Actually, I think they're already on the Blue Typhoon now that I think about it," Sonic gave his response as matter of factly.

Tails nearly jumped through the roof when he heard that,"WHAT!?" Sonic just sighed.

"Yeah I know, but listen, you kept shutting yourself from the world. Plus I still hold that backup access key," Sonic smirked. Tails gave an irritated look before giving a loud groan.

"When… do we leave for Earth?" Tails asked the question Sonic wanted to hear.

"Well, if we hurry and pack all your things with us, we might be able to leave in an hour; assuming that everyone is ready to go of course." Sonic stated while putting his hand under his chin.

"... what of the master emerald?" Tails asked kinda blatantly.

"Damaged but it should be enough to get us to Earth, which reminds me: isn't Earth in an alternate reality or something?" Sonic fiddled with his hands will saying that, making Tails slightly roll his eyes

"Yeah, but the wormhole should be powerful enough to cut a hole for us to travel to that reality, provided we have something to tell what reality Chris and Earth is in. Otherwise we would end up on a different plane of reality like everyone was super edgy, or we time traveled to the past, or we -"

"Your blabbering again," Sonic shook his hand while cutting Tails off from his… whatever it was, Sonic didn't know, just blabbering he supposed. Tails put a hand behind his head in embarrassment and gave a small sorry," point is, do we have something with Chris' DNA on it so we can track it's emissions back to where his reality is?"

"You bet!" Sonic exclaimed while pulling pieces of papers, seemingly out of nowhere, from behind him. Tails jumped up from his seat and snatched the papers out of his hands, a smile of confidence was cast on his face. Sonic smiled as walked over to his happy, foxy brother and put his hand of his shoulder. Tails looked up at his big bro when he did that.

"Listen, why don't we pack up everything so we can leave Mobius in an earlier time, okay? Then we can fix up something to get us to Chris's reality or whatever," Sonic said in a comforting, clam voice. Tails gave a smile," sure, but you ARE gonna help me, right?" Sonic have a small chuckle and nodded.

Over the course of 2 hours, the duo work tirelessly trying to pack everything Tails had to take. Sonic took packages of items to the Blue Typhoon and back with his amazing speed, while Tails worked on both trying to fit everything inside of small boxes and figuring out how to make the wormhole drive able to get to Chris's dimension. After getting all of Tails' stuff packed, the 2 raced each other to the ship just like the old times. Tails, not using his twin appendages like he should have in 6 months was slower than usual, but managed to keep up with Sonic's speed. At the entrance to the Blue Typhoon, everyone greeted to two as they approached the ship. They mostly gave hugs and welcomes to Tails since he hasn't showed himself in 6 months, but no could forget to greet the speedy hedgehog as well.

The team got to work on making final adjustments to the Blue Typhoon, as Tails fixed up the Wormhole ring to break through realities and Knuckles trying to help Amy fix the damaged master emerald to the engineering section of the ship. However Sonic noticed something about Tails within the past hour or two: Cosmo. Where was the pot he put the seed in?

Sonic approached the fox while he was working underneath a console. He called out to him,"Hey Tails!"

Tails jumped when he heard Sonic's voice, but forgot he was working underneath a console and bumped his head on the metal. Tails rubbed his head in pain, while a small, red bump made itself known to the two of them.

"Ow, Sonic!" Tails cried out in pain as he put his hands on his head. Sonic laughed a little and helped the poor fox out.

"Hehe, sorry to scare you bud, but I need to ask you something," Sonic said.

Tails gave a confused glance,"uhh, okay? What is it?"

"Cosmo, you never took her with you or packer her pot ready to go. Why is that?" Sonic asked.

"I did take her with me, not in a pot, but…" as he said this he pulled out a necklace that was hidden from view in his fur. What was behind a glass lens was a lone seed. Sonic was shocked on how fast he made that for her, and the fact he never noticed him not only building it, but actually wearing it.

"Yeah, her pot is… memorable and all, but hey, it's annoying to carry sometimes. Especially when your working while a friend bugs you and makes you hit your head on a console!" Tails said in a slightly frustrated voice referencing what had happened minutes before. Sonic wore an embarrassed smile, gave a small "sorry", and walked off.

' _Well, it's nice to see that he isn't camped in his room,'_ Sonic thought as he dashed away from the busy fox. Tails on the other hand was finishing one last thing before Amy's voice came on the intercoms.

"Hey Tails! We got everything set up and ready to go! Just waiting on your signal for take off!" Amy called out from the speakers.

Tail got up from the console, careful not to hit his head again, and looked at the console. He read all of what it had to say, but the thing he truly saw was the word that was in bold green that read: stable. Tails jumped up and clicked a button on the console," Amy, fire up the engines! We're good to go!" Amy gave a mhmm through the console before Tails shut it off. Once he turned it off, Tails darted to the bridge. He ran as fast as his legs would take him.

When the fox got to the door that opened up to the bridge, he paused for a moment and sighed. There was some nostalgia left in here, as well as painful memories, but Tails couldn't let that hurt him. Not now, his friends needed him. Slowly, Tails walked to the door, were it opened automatically and revealed the bridge to his eyes. Everyone was looking at him with smiles on their faces, watching him as he ascended to his chair. He glanced at them for a moment before saying," well don't just stand there! Let's go!" Everyone gave a slight cheer before getting into positions.

Slowly, the Blue Typhoon began to rise with a loud hum. The force of its ascent made trees fall over and bend as if controlled by the ship. As the ship began to make its way to orbit, all the crew and passengers gave one last goodbye to their old home. They were sad they had to leave, but looked forward to their new homes, memories, and friends they will make along the way. The ship got to orbit, were everyone saw how bad Mobius was in. Many areas of the main continent as covered in industrial buildings, there were little trees around, and small areas looked completely decimated. Tails swore he could hear Cream crying in the background from the sight of the planet. Regardless, he had to think of the task at hand.

"Knuckles! Is the master emerald ready?" Tails called through the comms.

"Yep!" Was all he heard.

"Okay! Activate the wormhole sequence! Target: Earth!" And with that, a wormhole opened in front of them. The ship passed through with ease as the hull was completely engulfed in beautiful lights; however, no one saw of the evil that followed them through the wormhole. Twirling it's mustache evilly with maniacal laughter…

* * *

 _Meanwhile in the Underground…_

"I JUST KNOW THIS DAY WILL BE DIFFERENT, SANS!" Papyrus said in his loud voice.

"why do you think that, paps?" Sans said in his usual lazy voice.

"BECAUSE! TODAY IS THE DAY I FINALLY CATCH A HUMAN!" AND WITH THAT I WILL FINALLY BE ABLE TO MAKE UNDYNE PROUD AND JOIN THE ROYAL GUARD! NYEH HEH HEH HEH HEH!" Papyrus proclaimed as he posed in a cool stance.

"yeah, sure bro," Sans replied back,' _it's not like your gonna die for 27th time in a row or anything…man… i really hope something new and interesting happens to make my bro feel happy'_ What Sans wouldn't expect, however, is the certain events that will take place in the future… for his sake, and the rest of the Underground…

* * *

Chapter two is done! Phew! That took me what felt like days to write (or in this case, type). Hopefully this is a better chapter than the first! Also! In the next chapter, I will be teasing a new crossover that my friend and I are working on! So let's see if you be able to catch what is in the future!

And HAPPY NEW YEARS TO ALL!


	3. Chapter 3: Until Chaos Ensues

Chapter 3! YAY!

Like I said in a previous chapter, I will be foreshadowing a future projects that I ma working on with a close friend of mine! Whoever can get it first will get a shoutout in the next chapter! Lets see who can find it first….

During this time, I'm gonna research more of my two universes I want to collide. And apologies for the downgrade of quality in this chapter, I have been rushed with my school starting up again. It may halt my uploads more to at least once a week (but hey, can't argue with more time to prepare in a sense). Welp, I talked too much, here's your next chapter.

* * *

As the Blue Typhoon dropped out of the wormhole, Tails began to frantically press buttons on his chair pad to see where they were. However, just before the scans finalized, a blue planet made itself known to Team Sonic.

"Tails, which planet is that? I can't help but feel like I've see this planet on a map of Chris' Solar System," Sonic stated while looking at the blue, cloudy giant from the window of the bridge.

Tails gave a smile before cheering," that's because it is! WE MADE IT!" All of the crew gave a cheer before Tails gave an very audible fake cough. Everyone one looked at him with confusion covering their faces.

"The only thing is, we need to know of this is the right dimension. Otherwise we can't risk making ourselves known to a different race of humans," Tails stated, killing the overall joy a little. Everyone murmured with 'true' and 'yeah, he's right' before settling down.

"Amy, set a slow course to earth, but try to keep out of sight from any telescopes or satellites in the air," Tails commanded as Amy just rolled her eyes and reluctantly did as she was being told to do. Meanwhile, Tails went to a console below him to open communication to see if he can make contact with Earth. Tails flicked a few switches and buttons before the screen in front of the bridge went live with static. Everyone in the room became completely silent before Tails gave a loud sigh and opened a hailing frequency.

"Hello? Chris? Chris, you there?" Tails asked through the monitor," Chris?"

* * *

 _On Earth…_

Within a laboratory, a young boy named Chris was working frantically on a machine that will hopefully communicate with Sonic and the others. 6 months have gone by with little progress, only static, nothing… just emptiness.

Chris was overwhelmed with the work he had to do; not only did he have to make this device, he had to help with upgrading procedures with military tech and keep an eye out for any sign of remaining Eggman forces left on Earth. Groaning, the boy began finalizing adjustments to try and communicate with the rest of the team. Screwing in the last bolts and plugging in the equipment for it to even turn on. Chris wiped the sweat of his head after he finished tightening the last bolt in the machine and smirked. If only his friends could see him now…

Booting up the machine, Chris help high hopes to make contact. His eyes lit up as the machine's monitor began to light up. It was working, IT WAS WORKING! Chris was about to jump for joy when he heard an alarm coming from the device. It made an annoying beeping sound and began to malfunction until a few circuits blew and the machine shut itself off. Chris looked at it for a few moments before he threw papers around in rage. He screamed in frustration and he gave a hard kick to the bottom of the machine, slightly bending the metal in the process. As soon Chris started to walk away from the machine to cool off, he heard something behind him. He hurled to see the monitor trying to pick up something. Chris wondered if he had accidentally picked up a nearby television broadcast and was about to shut it off when he heard a voice that made him nearly cry.

"-is? Hello? Y.. re?" It was static-ky, but he instantly recognized the voice: Tails.

Chris hurriedly press a blue button that would allow him to see and hear to whoever was communicating with,"Hello? Tails?"

The signal became more clear and a face began to show itself on the monitor.

"Ch-s, can you hear me?"

"Loud and clear, Tails!" Chris said with tears in his eyes. He could hear a cheer in the background momentarily before the signal glitched a moment.

"How did you manage to get into contact with me?" Chris asked a kinda stupid question, but he didn't really see the back of the Blue Typhoon's bridge.

"We're on the Blue Typhoon! Question: is there a place we can land? This signal is really weak and it might be better to answer each other's questions in person," Tails concluded.

"Land near the the airfield. I'll see if I can get access to allow you guys to land there!" Chris replied.

This time Sonic stepped in to say something,"will do kid! And Chris, nice to see ya again!" before the screen cut out. Once the chat ended, Chris darted to his car, knocking over many of his books and papers along the way. He pulled out his phone and phoned Topaz.

"Hey Topaz, can I speak to someone in charge? I have very good news! Team Sonic is returning!

With that, an area opened up for the Blue Typhoon to land; and as of right on cue, the ship came into view and slowly descended to the surface. The size of the ship up close still amazed Chris, as well as everyone around him. When the ship touched down, an immense shockwave nearly threw everyone off their feet. Many military airplanes were present, in case of an attack or something Chris deducted. As the ship opened up, the inhabitants inside began to pour out of it, many ran to Chris and attacked him with hugs and laughter. Several of the guards became alarmed at first, but when they realized it wasn't harmful in anyway they went back to a stationary posture. While talking to Cream and Cheese, Chris caught a glimpse of the two he really wanted to see. Standing near a couple of his old friends, Sonic and Tails were talking to them. Chris raced past a few Mobians and guards to get to the duo, yelling," Sonic! Tails!"

The two looked at the approaching friend of theirs and prepare for embracement. As Chris reached the two, he pulled Tails into his arms and gave him a big, lung squishing hug. Sonic just snickered and walked over to the excited human.

"Aw man, it's so good to see you guys again! I missed you guys so much!" Chris cried out in pure joy, while Tails couldn't say the same in his situation.

"Ack! Chris… can't… breathe….," Tails barely managed to gasp out from the bear hug. Chris put him back on the ground with a sorry, an exaggerated embarrassed sweat drop could be seen on his face.

"Anyway, you guys wanna come over to my lab? It's not far! Plus, I think I have something you might find interesting, Tails!" Chris suggested with a certain passion in his voice.

"Sure," Tails' eyes lit up like stars as he walked with Chris and Sonic to Chris' car. The trio got set up to go to Chris' lab, with Sonic riding, or in this case lying on top of, Chris' car. While riding, they made general small talk before the major questions were about to fired at in the lab. When Tails got to the building, he was confused for a moment. It looked like every other building in the city. However, when he walked inside, he judged its size too early. The space was MASSIVE! And there was a telescope in the back, too!

"Man Chris, your hobbies and interests musta changed, since when did you like the color purple, old folk tales and… dragons?" Sonic inquired to his human friend as he picked up a dragon off of a desk.

"Hehe, yeah. After I returned, it kinda happened instantly. I didn't understand how or why at first, but overtime I just grew into it!" Chris returned, but knew what he had to say, this was strange that his friends just came back like this. Something must've happened.

"So, what made you return to Earth? I know your pretty stubborn, Sonic, so it has to take something major to make you want to leave your planet," Chris asked, not aware of what had happened. Upon hearing this question, the two Mobians looked down, Chris knew instantly that something horrific had occurred. He had to know," what happened..?"

Sonic raises his head to look Chris in the eyes,"After you were shuttled away, Eggman began to work on new technology. He used what was left and what he knew of the Metarex technologies to make new super weapons… It got so bad, we couldn't barely make a dent in his forces. When we destroyed one, dozens more would show up." Chris' hand was over his mouth in shock. How? How did Eggman do this right AFTER he had left? How did he not notice this before?

Sonic continued," within 4 months, most of the planet had been… conquered…" Chris heart shattered. He didn't know what to say, he looked down with anger as tears flooded his eyes.

"However," this caught his attention," 2 months ago, we went dark. Nobody has seen or heard from him, so we used that as a sort of vacation at first. But when we saw Mobius had no chance to be retaken, we abandoned the planet. We managed to get Tails to fox up our wormhole… thingy and well,you know the rest."

Chris wanted to cry just from hearing that, but he had to be strong for his friends. He looked at the two, they looked like they were gonna cry, too. An idea popped into his mind that would comfort them, and took the initiative.

"Hey, what do ya say we head to the mansion, get something to eat?" Chris comforted his friends as he wrapped his arms over their shoulders.

"*sniff* sure, Chris, that sounds good," tails choked up as the trio left the lab.

* * *

 _One month later_

Tails was lying on a bench next to the garage near the Thorndike Mansion. It had been almost a month since the reunion, and it did still feel like yesterday when he saw Chris for the first time in 6 months. It's been a month, no sign that Eggman had followed; so this is what true relaxation is like. Tails was about to fall asleep when he heard a loud screech nearby, followed by a "Yo, Tails!" Tails opened his eyes to see Sonic in front of him, wearing his cocky smirk as always.

"Oh, *yawn* hey Sonic," Tails stretched as he sat up on the bench, rubbing his eyes.

"I was thinking: how about we take that new drive of yours a spin by a race! And besides, there is a mountain I wanna go look at!" Sonic said, rubbing his finger underneath his nose. Wait: Sonic wants explore a mountain? That's a first. Plus, Sonic is right: he needs to test that new drive. Why it against the fastest thing alive? Everything was fine and dandy already, so he didn't have to worry about Eggman attacking.

"Ok! Your on!" Tails raced into the cockpit of the X-Tornado. He flicked a couple buttons and the plane turned on. The engines began to roar with life as he moved his plane to the runway. Sonic got into a ready stance beside the plane.

"Alright, the mountain is just ahead of us by about 25 miles," Sonic snickered a little at the pun he made by accident.

"Hey!"

"Ok! I'm sorry, now are you ready?" Tails gave a nod and the cockpit glass closed on the plane. Sealing the piloting fox inside, Sonic just smirked and got on his hands and knee.

"Ok, on your mark! Get se-," but Sonic was cut off by a loud whoosh as the X-Tornado suddenly took off, and he got annoyed,"hey, cheater!" And rushed to catch up.

The trip to the mountain was filled with laughter and a slight bit of annoyance. As the duo approached the mountain, tall trees prevented Sonic from seeing ahead slightly, forcing him to look to his flying brother for guidance.

"Hey, bro. Are we there yet? If you see a giant mountain without snow on it, then we're here," Sonic states the obvious since it wasn't winter yet.

"Yeah, I see it, Sonic! We're just about th-," before Tails could finish his sentence. A large, red laser beam appeared out of nowhere, instantly slicing the ship and causing it to give a small explosion. Sonic stopped running and watched in horror as the X-Tornado plummeted to the ground and a massive explosion could be heard ahead of him.

"TAILS!" Sonic yelled at the top of his lungs as he raced to the place of the crash occurred. It felt like time around him stopped as he raced through the forest. Upon reaching the crash site, his pupils (small already), shrunk even more at the sight. Trees and the plane around him was ablaze. It looked like hell itself had suddenly appeared to him and him alone. He shook the thought out of his head, he had to find him. He had to find Tails, then kick whoever's butt that did this. He didn't need to search that long as his gaze fell upon the ground away from him, he nearly puked. There lying burned, bruised, and bleeding was his foxy brother. Sonic raced over to him and pulled him into his arms, crying in the process.

"Tails? TAILS? CMON BUD! STAY WITH ME!" Sonic cried out as he felt the the fox's neck. He felt a pulse… A PULSE! HE'S STILL ALIVE! Thank God! Sonic pulled Tails away from the wreckage to check the injuries, but an ominous hovering noise behind him made him twitch. Sonic placed Tails on the ground gently to see who he had to fight, and who he saw made his heart stop as much as the crash. There hovering above him, twirling his mustache around, cackling evilly, was Dr. Eggman!

"OHOHOHO!" Eggman laughed hysterically, no, madly. Making Sonic very angry, he balled his fists," Eggman… what have you done..? WHAT HAVE YOU DONE!?"

"What I'm going to do you, as well," as Eggman snapped his fingers, Decoe and Bocoe suddenly appeared out of the bushes and fired a grappler at Sonic. He tried to dodge, but it caught him off guard, and they wrapped around his arms and legs. The main thing is he started feeling, weaker?

"What… what are you doing to… me..?" Sonic gasped out as he was forced to the ground.

"Well, I'm glad you asked! You see, I needed a find a way to nullify your speed so I can capture you with little to no resistance. And low and behold: the Cuffs of Drainage!"

"Really..? I felt like… you still… could work on… your naming," Sonic wheezed out.

"Take him," Eggman commanded as the two robots began to take Sonic. He tried relentlessly to escape, but he couldn't…

* * *

 _With Tails…_

He began to hear voices.

"..ur naming," "take him." Slowly, Tails began to rise to see what had happened, but was greeted with immense pain. He grunted and looked at the landscape around him. All hell had broken loose as flames erupted everywhere, and for a moment he thought he was in hell. That was until he looked left and horror filled his eyes more than he thought they could. Sonic was being taken away by… EGGMAN?! HOW!? He tried to stand and fight but helped in pain as he tried to hobble close. Everyone turned to see the kitsune standing and Sonic had hope and horror filled in his eyes before he yelled," TAILS! GO RUN! UP THE MOUNTAIN! JUST GO!" and with that Tails traveled as fast his legs could take him up the mountain.

Eggman saw this and retaliated," you too! Follow him! Hand me the Cuffs first!" They did as they were told and ran up to catch the fox. Sonic gave a determined "NOO" and tried to take down Eggman, but it had no avail. Eggman laughed as a claw appeared and clamped to the cuffs so he could fly the Egg-Pod.

"Now them, lets go fox hunting!" Eggman cackling evilly as they ascended the mountain.

Tails was hobbling as fast as he could up the mountain. He couldn't fly or run, JSU hobbling. From a distance he could hear clanking of metal behind him. Tails turned around to see Decoe and Bocoe chasing him. Tails screamed and ascended the mountain faster. He was running out of breath, everything hurts, it's just all pain. He looked up to see a ridge leading to a cave, and figured it would be a good place to hopefully hide, or at least make a last stand. He climbed with all his might as he reached for the ledge to get on it. The lipoid clanging of metal below him was growing louder, and Tails knew he couldn't outrun them in his state. He manage to get on the ledge and hobbled as fast as he could to the cave, only to come to a screeching halt as a ominous hole laid in front of him.

"Oh you gotta be kidding me!" Tails yelled in frustration, only to realize his mistake.

"I found him sir!" A robotic voice echoed in the chamber. Tails turned around to see the two robots, along with Eggman floating in his hovering chair of death. A claw was holding a powerless Sonic captive.

"Sonic!" Tails cried to his older brother

"Tails! Don't do any-," Sonic was interrupted by a blow to the back of the head by Eggman, wielding a small laser pistol. Pressing a button, Eggman hopped out of his egg-pod and slowly approached the fox, pointing a pistol at him. Tails began to panic and moved closer to the edge of the hole before nearly falling over due to being backed off. Sonic watched helplessly at the scene, watching it with a horrid look in his eyes as Eggman approached Tails. He turned around still pointing the pistol at the fox. Eggman's evil smile somehow became more evil than ever.

"You see this, Sonic? This… is what happens when you attempt to leave our game," and with that he pulled the trigger. A small red bolt struck the poor fox in the chest leaving a large black spot in his chest. Eggman walked over a few steps to the fox, and barley kicked him off the edge…

Sonic was screaming as the scene unfolded and cried as Tails began falling down the hole… he couldn't believe it… Tails, his brother, dead… His ears caught back to Eggman's laugh as well as the robots. As Eggman looked down on the pistol, he noticed something was off.

"Darn it! The setting was on stun! Not kill! Well whatever, my scan revealed that this hole is hundreds of feet deep there is no way he could survive that! Now come on you two. We have a world to take," Eggman spoke as he and his robots boarded the now cramped egg-pod, along with a heartbroken Sonic…

* * *

 _In the Underground…_

Sans was asleep at his post, as usual, when his brother Papyrus arrived to give his lecture again.

"SANS! GET UP YOU LAZYBONES! AND STOP SLEEPING AT YOU POST!" Papyrus boomed, waking the lazy skeleton up.

"i wasn't sleeping, just… uh, seeing the back of my skull?" Sans lied. Papyrus was about to lecture him when out of nowhere, a small earthquake shook the area. No, not just here, the entire UNDERGROUND. Snow began to fall off of trees and rocks, beverages, and the conveniently shaped lamp began to shake. Then as soon as it began, it ended instantly. The brothers looked at each other before Papyrus spoke as usual.

"WHAT WAS THAT, SANS?" Papyrus question.

"i dunno, felt like an earthquake," sans responded with an already known answer.

"I KNOW THAT, BUT WE NEED TO GO TO SNOWDIN TO HELP ANY MONSTERS IN NEED!" Papyrus commanded as he took off for Snowdin.

' _well, things just got interesting,'_ Sans thought to himself as he teleported to go help his brother out.

* * *

UGHHH… I MADE THIS AT 3AM…

Anyway! Hopefully you did enjoy the latest segment of Undertails. Review it on your way out!


	4. Chapter 4: Welcome to the Underground!

This is it! The moment that everyone has been waiting for! The main event!

Note: I will be primarily be focusing on Tails' side of the story, but i will go back to Sonic from time to time. Also, I will try to pump out chapter 5 as well as my new project I am working on, but when? As fast as I can, but my school starts this upcoming Monday, so my stories will be put at a halt to at least per week.

Can I request something from you viewers? Please tell me what I need to work on, it'll help me better understand where i need to address my issues and pump out better content for you all to enjoy!

Anyway, with that said, chapter four… begins...

* * *

' _Where am I? Ugh… what is that light? Is this… Heaven? Ow… nope, can't be if I'm feeling so much pain!'_ Tails struggled to shield his eyes from a beam of light hitting him directly in the face. Tails looked away for a few moments before his eyes adjusted to the amount of light. His eyes darted around to see where he was, but he couldn't say much since he was lying on his back. As Tails attempted to get up, he was greeted with an immense amount of pain. Tails cried out in agony as it hit him with full force. Slowly, he managed to get into a sitting posture to assess his injuries.

He was traumatized at himself, almost wishing he was still unconscious so he wouldn't see himself. He was cut and bruised everywhere, with large blood gashes on his arms and legs. Looking down, Tails noticed he apparently landed in a bed of golden flowers, well… mostly golden. Many that surrounded him were covered in blood. By this time, Tails noticed the big black singe mark on his chest, making him wonder how we survived all of this.

' _I don't understand how I'm alive. Well, that crash, sure, many people do and don't survive this kind of things and I guess that was my lucky moment being able to walk away from it. Eggman's blaster… the only way I could've survived that was if it was on a low power setting, but that's unlikely… he'd probably want to make it swift and fast… or it was on stun. Judging by the singe and size of the mark, I'd say he left it on stun, heh… typical Eggman, forgetting something minor in the wake of his plans… That fall though. I should've dies_ _ **here**_ _at least, did these flowers, cushioned my fall? Unlikely…'_ Tails philosophical mind began racing for answers.

' _Well, all those questions can be answered later, right now: I need to get out of here!'_ Tails thought to himself as he tried to stand. As he rose up, he felt his legs shake immensely before giving out and making Tails fall on the floor with a solid **thud**. Tails was just too weak to try to stand by himself, needed something to lean on. Out of the corner of his eye, Tails saw a rock wall close by. Reaching his bloodied, bruised arms, he began to crawl; trying desperately to reach the rock face. After what seemed like hours of grunting and struggling, Tails finally reached the wall. He reached his hands out grab one of the rocks, getting a grip on the largest one possible. Slowly, Tails began to pull himself up, using all his strength to keep himself balanced upright. After successfully managing to get up, Tails looked up towards the light.

' _My twin tails should be able to carry me out of this hole, just gotta hope it isn't too high up. Otherwise I might be stuck here forever, or until Sonic and the others can rescue me,'_ Tails thought to himself as plan began to unfold. Tail let go of the rocks, almost falling in the process, and using all his might, he tried to fly up. But as soon as he even moved a hair on his twin appendages, he was greeted with an immense amount of pain that put him back on his hands and knees. His tails hurt so much it nearly made him cry. Tails looked back to see his tails, one of them bending in the wrong way.

' _Oh no! Without my tails, I can't fly out… that means… I'm stuck here…'_ Tails thought solemnly as he attempted to move his tails again. This time, the left tails gave a tiny flick, giving Tails hope.

' _Okay, so I can still move one my tails… kinda, it'll need time to heal. Ugh! How am I supposed to get get out of this!'_ Tails thought frustratedly as looked up at the light above. Tails noticed something to his left that he probably should've seen earlier; there was a cutaway in the cavern. Curiosity hit Tails as he tried to stand up, only to fall back down. He managed to get back to the wall so he could lean on it to move around the cavern. He manage to limp his way to back of the hole, but a sudden coughing attack hit him. Tails coughed up some blood and his voice began to sound a little raspy. Fortunately, he only coughed up blood only that once as he continued on to the back.

Tails looked and saw a doorway, at the top containing a strange symbol, which raised an eyebrow.

' _People live down here? Well, I hope they're friendly and can help me out,'_ Tails thought as he looked at the symbol. The thought of people down here reminded Tails of an old folklore he heard Chris talk about: an ancient Viking civilization use to throw people down holes to kill them off, but some survived a little by using the underground resources to live in shacks. However, they might have lasted only a few weeks before dying off. Tails hoped the same thing wouldn't happen to him as he went through the doorway. Tails looked through to see another light shining upon another bed of flowers and yet another doorway on the opposite side. Feeling determined to press onward, Tails let go of the rock wall he used for stability as he limped toward the frame. Coming closer to the bed of flowers, he noticed all but one were facing him, which was kind of strange. Tails blinked to see if he was hallucinating, only to see that flower turned around… with a _face!?_ It's eyes were closed, and it looked cheerful.

"Howdy! I'm Flowey! Flowey th-," It was cut off by Tails screaming. It too stopped, looked at who he was speaking to, and screamed when he saw the Fox. Tails fell on his butt and scooting backwards away from the flower, still screaming. The screaming lasted for a full minute before the two calmed down and out of breath.

"What the hell are you!?" The flower yelled out toward Tails.

"What am I? What are you?" Tails responded the same way as the flower.

"Okay, okay. Calm down there bud. I'm not gonna hurt ya, ok?" The flower tried to coax the scared fox from having a panic attack again.

"W-Who and _what_ are you,? Tails asked, putting an emphasis on the what.

"Well, like I said before I was _rudely_ interrupted, I'm Flowey! Flowey the Flower! And you are?" The flower, Flowey, responded cheerfully.

"Well, I'm Tails, and where exactly am I?" Tails responded with a question . Flowey's smile grew.

"Your in the Underground!" Flowey states as if it was supposed to mean something.

"Okay? Well, I think I'm lost, could you help me out?" Tails asked.

"Sure but can I ask a couple of questions first?" Tails nodded for him to go on," right. First off: what _are_ you? Your not a human and your not like any other monster I've seen before."

"I'm not a monster," Tails yelled in offense.

"Sure you aren't, and I'm not a soulless being!" Flowey responded.

"...what? Anyway, to answer your question: I'm a Mobian," responded with some pride in his voice.

Now it was Flowey's turn to be confused," what the heck is a 'Mobian'".

"Well, in a nutshell: were a race from a different reality," Tails stated as matter of factly. A simple "oh…" came from Flowey before he shrugged it off.

"Anyway, your new to the Underground, right? You must be **so** confused! So will need someone to teach you the rules here. Since there's nobody else around, I guess little old me will have to do." Flowey just then noticed the condition this Tails fellow is in. He was banged up really bad.

"Before we begin, what happened that caused you to be so banged up? You looked like you came from a war zone, did you come from a war zone?" Flowey asked, raising an "eyebrow" as he examined Tails.

"Honestly, I don't want to talk about it," Tails responded with a sad tone. Flowey just nodded.

"Okay! Ready to learn the rules of the Underground, kid?" Flowey asked. Tails just gave a nod," Okay, here we go!"

Instantly, the room around flashed black a few times before a black box surrounded the two of them. This scared Tails, but Flowey seemed perfectly calm in this, so Tails trusted him with it. Tails looked at himself, his orange, blood soaked fur became a grayish color, yet the color of the blood still remained. It wasn't very noticeable, but it was there and he could see it. His white chest was still the same color, despite the stains. As he looked down at himself, a little orange heart with a reddish tint and background appeared in front of his chest, scaring him. Flowey began to say something.

"See that heart? That is your soul, the very… culmination… of your… being…" Flowey's voice trailed off as he looked into Tails' soul, literally.

"What's wrong? Your voice trailed out. Is something wrong? Is this supposed to happen?" Tails frantically asked questions to see what was happening.

"Kid… we need to talk…" Flowey said with a serious voice.

"Uhh, Okay? Is something wrong with my soul?" Tails asked, tilting his head and raising an eyebrow in confusion.

"You said your not a monster, correct?" Tails nodded," and by the looks of it, it's established your not human… but this soul… it's in the shape of a human's," Flowey stated.

"How? I'm not human!" That was all Tails could say.

"I'm not sure, this is definitely the strangest thing I've ever seen before. A

non humanoid with a human like soul. Fascinating…" Flowey stated, but what got Tails was the way Flowey said "fascinating". It sounded dark to him.

"Not only that, but the color is interesting, too!" Flowey look at the soul.

"Is it normally a different color?" Tails questioned.

"Well, as far as we know, there are at least 7 different human traits that goes along with souls. Red, for example, goes with Determination; orange for Courage or Bravery, just depends on how you look at it; yellow for Justice; green is for Kindness; Blue is for Integrity; cyan is Patience; and purple is for Perseverance. You see, a monster can't 'have' these traits in their souls. It's just not compatible with their soul structure, but they do show the personalities. A monster's soul is upside down for you, and it's white, which means it can't take on the traits like human souls can. Wanna know something interesting too?" Tails nodded, knowing at the extent of the information, but he had to know what was going on here," by the looks of it, you have not only one p, but traits in here: Bravery _and_ Determination. I don't think we've encountered something like this before," Flowey stated.

"Huh, neat," was all Tails could say. Flowey looked at Tails hp: 3/20. _'I need that soul, but my attacks can't kill him yet, he needs to watch it happen…'_ Flowey plotted in his head as he continued on.

"Well, anyway, no with that out of the way, let's continue! Now, your soul starts off weak, but it can get stronger with a lot of LV. What's LV you may ask? Why LOVE of course, and you want some of that, right?" Flowey said strangely, which Tails only sweat dropped. Flowey winked and multiple white pellets surrounded the injured fox. Tails jumped back at this, but Flowey held a reassuring expression.

"Uhh, What are these things?" Tails asked nervously, seeing them all around him.

"Woah, relax friend! Down here love is shared through little, white, 'Friendliness Pellets', plus they will heal you up since you could use that right about now," Flowey said in a fake way that wasn't apparent to Tails.

"Wow, these things will heal me?" Tails asked obliviously.

"Why yes friend! Now move around get as many as you can!" Said Flowey enthusiastically. As he said this, a small pellet in front of Tails slowly approached him. Tails reached out his finger to touch it.

"Wow! Thanks Flowey! You shouldn't ha-," Tails was interrupted by a stinging sensation when he touched it. No, didn't just stung, it _hurt_. As Tails gripped his hand in pain, evil laughter came from the flower as the pellets around him suddenly shot at him with blazing speeds. They ripped through his fur and flesh and into his body, only to shoot back out the other side. _It hurts so much_ … the pain brought Tails to his knees and he looked up, Flowey's smile became a huge face of pure evil. It was something Tails didn't want to wake up to, it was a nightmare alive in a fleshy, flowery body. Tails could barely hear anything from the ringing in his ears, but could definitely hear Flowey scream, "YOU. IDIOT. IN THIS WORLD. IT'S KILL OR BE KILLED. WHY WOULD ANYONE PASS UP A PN OPPORTUNITY LIKE THIS!" As he said this, pellets surrounded the poor fox, who was trying desperately to stay awake.

"DIE." Flowey laughed as the pellets surrounded the fox slowly caved in on him. This was the end for Tails, as he closed watched them close in he braced for impact, but it didn't happen. He heard a sound and they instantly disappeared. Flowey too, looked confused before a fireball mysteriously appeared to his left and shot at him. Flowey look at his left to see this fireball hit him in the face and go soaring away. Tails barely could keep up with what happened, as the only thing he last saw was a woman running at him, saying "My child!" before the darkness claimed him as his next victim…

* * *

The woman saw what happened to that poor creature and knew she had to help it.

"My child!" She cried, but it had fallen unconscious. Racing up to the injured creature, she reached her hands out to it. A warm, soft green glow encased her hands as she attempted to heal it, but nothing was working. She looked at its hp: .0024/20. She attempted it it again, but it did nothing. The creature's hp was still going down:

.0020/20. Why wasn't it working?

"Come on old lady, you can do this!" She said to herself as he spouses all her might. Her head began to hurt as she pulled more and more strength into healing this monster, until she collapsed. She had failed… tears began to form in her eyes as another creature was about to pass in front of her, but she heard a strange noise. She looked up and hope began to fill her eyes once again. It's hp rose! 0.1/20, to 0.45/20, up to 1.3/20. Nodding to herself, she carefully picked up the creature and began to run. She ran as fast as her legs could carry her and this monster. No time to lose. She passed by many of the puzzles, traps, and monsters, all of which looked at her when she carried the wounded creature.

The lady made it to her house, where she darted to the spare bedroom she had just in case. She placed the monster on the bed and ran to her bedroom, grabbing her medical essentials before running back to the other bedroom. She gasped in horror as the monster's hp began to drop again. She used her healing magic to keep its hp steady as she cleaned up some of its wounds, getting groans of pain as she did so. She applied bandages to the most wounded parts of its body, sweat running down her face in the process. After what felt like a half hour, she fell on the floor, gasping for air. She manage to keep this monster from not dying on her. She took a look at its hp, holding steady at 2/20.

Looking at it, she couldn't help but wonder where it came from. It's not like any other monster she's seen before, so where did it come from? Did it cause the massive earthquake? A thought ran into her mind. Perhaps that monster behind the door knows more.

* * *

Sans and Papyrus raced to Snowdin to find any hurt monsters or any that were in need, but to their surprise, non was required. Nothing major had been damaged. A few letters fell off its signs, but that was repairable. With that out of the way, Sans now had another matter at hand: finding the source of the earthquake. Maybe Alphys knows more? It's a good idea to see if she can find anything that will help him out.

' _Maybe I should check on that old lady behind the door first, then find alphys,'_ Sans thought of a plan as he walked to find his bro talking to Grillby.

"hey bro, i'm heading to alphys' lab to check on her and find what happened," Sans called out.

"OH, OK SANS! BE CAREFUL OUT THERE! CALL IF YOU NEED THE HELP OF THE GREAT PAPYRUS! NYEH HEH HEH!" Papyrus posed in a cool stance, which Sans just gave a thumbs up before teleporting away. Sans reappeared to a giant purple door, he walked up to it and sat down in front of it.

He knocked on the door,"knock knock," to which there was no reply. He waited a few moments before trying again, this time knocking harder," knock knock,". Sans waited a few more moments and still heard nothing. He was about to try again when he heard a woman's voice fro, the other side.

"Who is there?" It sounded rough, like stressed rough, but Sans let that slide for now.

"cash".

"Cash who?" The voice replied.

"nah, but i'll take a peanut if you got them," Sans quipped. A laugh could be heard from the other side, making him snicker.

"hey, you alright from what happened with that earthquake?" Sans asked concerned.

"Oh, yes! Thank you, and may I ask the same to you?" The voice replied back.

"eh, everyone's ok, just some letters of signs. no big deal," Sans shrugging it off as if it didn't happen.

"Good to hear that no one was hurt, but I need to ask you something," the voice replied.

' _oh god'_ "uhh, yeah sure. what is it?" Sans asked.

"Have you noticed anything unusual lately?" The lady behind he door asked.

"nope, nothing new but a pile of twigs, why?"

"Something fell into the ruins just moments ago," the lady said. Wait _something_ , not a human? Huh, okay.

"is it a human?" Sans asked.

"No, it looks like another monster, but not like any other monster I've seen before! I saw it under attack by a flower. When I rescued it, it was about to die, but I healed it in a last moment effort. It's now lying on a spare bed resting," the lady commented.

"heh, nice," Sans gave a thumbs up, but she couldn't see it. He heard a sigh coming from the other side, he knew what was about to happen.

"Can you please, _please_ promise me something?" the lady's voice seem like it was about to cry, sans just listened to what she said," promise me. If that monster gets out, protect it, and help it! Keep it safe, will you?" Sans normally hated making promises, but a couple things came into mind. First, it's not a human, so it won't be attacked by anyone really; plus, it has magic, it can defend itself, right?

"ok, i'll do it," Sans agreed.

"You promise?" The voice replied with concern, sans looked away before sighing.

"i… I promise," Sans said weakly.

"Oh thank you so much!" The voice cheered.

The two sat in silence before Sans broke the ice," what did the skeleton say when another skeleton lied?"

"Tell me".

"'you can't lie to me! i can see right through you'," the lady laughed as the joke carried on for some time.

* * *

Chapter 4 is done! Will chapter 5 be out this week? Possibly, but I'm starting to develop my other projects so don't expect it to come this week.

As for the project itself, I'd say it's going alright. The project will probably be what I will post next so stay tuned for more info!

 **THANKS FOR READING! PLEASE R &R!**


	5. Chapter 5: Moving Out

HI! Apologies for my delay with this chapter! I've been putting so much effort into school and my other story (which you should read if you haven't already ;] ), its called: Legend of Spyro: Dragonriders' Destiny.

Oh, and I'm changing how I'm posting content. Im posting on a different story as frequently as I can make it [so… after this chapter has been posted, I will focus on making a new chapter on my other story, and when I post that next chapter, I'll come back to this story). Here's chapter 5 of Undertails!

And I apologise in advance if the chapter(s) ahead are quite crappy, I haven't been feeling to good with how everything is in my life. I think I'm stressed to a point where getting upin the morning makes me depressed…

Anyway! HERE'S CHAPTER 5! (finally, am i right?)

Tails' body was in so much pain. He felt like he had wrestled with everyone at the same time. Slowly, he opened his eyes to see where he was. The first thing he noticed was the fact he was under a bed quilt. Someone had taken him in under their house. He glanced around to see if he can understand more of where he was.

He was in a small bedroom. There was a closet at the opposite side of the room. A drawer was next to the bed he was laying in. He tried to sit up to see more, but was greeted with a sharp pain in his stomach. Tails grunted, but slowly continues to sit up. He let himself lean on the backboard as he took a few moments to rest. After a few seconds of pain, Tails threw off the covers to reveal his injuries.

He was bandaged all around, with a large portion of them covering his chest region. A few wrapped around his arms and legs. He noticed several large red stains on the bandages, too. He could feel one wrapped around his head and ears, as well.

' _The wounds must've been bad for this amount of blood to show,'_ Tails thought as he inspected them. Tails ears twitched when he heard something from the other side of a door. It sounded like footsteps coming towards him. He faced the door right as it opened to reveal a tall goat lady in the doorframe. She had on a strange garment, with a symbol on it. Tails glanced at the symbol, and a thought clicked into his head. That was the same symbol as the one on the doorway!

"Oh! You are awake!" The lady said as she approached the fox.

"Y-Yeah, I guess so," Tails replied, holding a hand on his head.

The lady seemed to have taken notice of his hand moments and asked, "are you alright, my child?"

"Yeah, just feeling really dizzy, and-," Tails stopped for a moment after what she just said, "wait, why did you call me 'my child'?"

"I am sorry. It is a habit of mine. Is there something else I should call you by?" The lady asked, slightly taken back at the fox's words.

"Well, for starters, my name is Tails. Who an-... who are you?" Tails asked. He had to remember what Flowey said. Sure he may have tried to kill him, but some of those things had to be true, right?

The lady smiled, "I am Toriel, caretaker of the Ruins. I found you hurt after encountering that flower. Is it alright if I ask you a few questions, my c- Tails?"

"Of course."

"Well, firstly, what kind of monster are you? You are not like any other monster I have ever seen before?" Toriel asked.

"I'm not a monster, nor human. I'm a Mobian, a different race of beings that inhabit the earth with the humans," Tails stated. This shocked Toriel. Not only of what he spoke about his race, but coexistence with the humans. Does this mean that they have a chance with the humans?

"Might I ask about you and your race?" Toriel inquired, to which Tails smiled. Over the next half an hour, Tails explained what has happened in the past, his battles, leaving his home planet; all of which made Toriel curious, but also very nervous and skeptical.

"I… see. Well then, next question: how do you feel?" Toriel proceeded with her second question.

"Feels like I have been crushed by thousand of boulders."

"I believe I might be able to help," Toriel smiled as she approached the two tailed fox. As she came closer to him, Tails became more and more nervous. She noticed this and attempted to reach out to his nervousness, "do not be afraid, my child."

"Yeah, but no offense. The last time someone said that, I almost died to a flower," Tails responded harshly.

"I promise, this will not hurt," Toriel tried to comfort the fox. Tails gave her a glare for a few moments before relaxing. She has done so much already, so this won't hurt him, right? He gave a small sigh and nodded for her to come closer. As she came to his side, Toriel stuck out her arms. Tails was confused at first, but he saw a small green glow emanated from her hands. It encompassed him and it felt… relaxing.

"How do you feel?" She asked, still doing… whatever it was to him.

"I feel... relaxed," Tails admitted as he observed his glowing green body, "what are you doing anyway?"

"I am attempting to heal you using my magic," Toriel stated.

"Magic? I thought that didn't exist," Tails replied, but it felt like more of a question.

"In your eye's, there is no magic within your world. To us, however, it is how we live, how we cook, how we do anything. Magic reflects who we are and how it is used," Toriel stated as if giving off a school lesson. Tails could only give a 'huh…' before continuing to let Toriel heal him. After a few moment, Toriel looked frustrated about something.

"Uhh… is something wrong?" Tails asked.

"For some reason, I am unable to heal you as one normally should be," Toriel frustratedly replied as she retracted her hands.

"Something tells me that isn't supposed to happen," Tails spoke.

"Yes, it should be healing you, but instead you seems to be rejecting it," Toriel gave a reply as her head hung low.

"Hey… its not your fault, you tried and you did your best. I mean, if it weren't for you, I would've died to a flower," Tails tried to comfort Toriel, while also trying to cheer her up.

Toriel gave a small chuckle, "I suppose so. Well, I have bothered you long enough. So please, just rest, I will check up on you later."

"You sure?" Tails asked, but noticed the bags under her eyes. It might be a good thing for him _and_ her to get some rest, "well, alright. G'night Toriel, thank you for all you have done."

"It is quite alright, now go to sleep, my child," Toriel smiled as she went out of the room, "goodnight, my child," she smiled genuinely as she slowly closed the door, leaving a sleeping fox on the other side.

 _Time skip brought to you via this line!_

A couple of days have past since Tails had woken up in Toriel's house, and it has been been fun being with her. She had always been there when he needed help getting up, making general small talk, and overall somewhat of a good fiend. In a couple of instances, he viewed her as a mother figure to him. Not only that, but she was an excellent teacher, too. She has taught him the true rules of the Underground, like using MERCY instead of FIGHTing. She showed him all of the monsters that accompanied her in the Ruins, how to use his new menu, and boy was that an adventure he would never forget… and she showed him her favorite snail hunting spot. It made Tails happy that there was someone down here that was filled with as much compassion as he does. However, as time rolled on, Tails' mind, heart, and soul grew heavier with guilt and regret. He knew he couldn't stay there forever, he had to keep going on, to find Sonic.

Tails was lying in the bed, trying to think. _Okay, I need to get out of this hole and try to find Sonic, I really hope he's okay. But I can't just leave Toriel… besides, she's done so much… maybe I can convince her to help me out!'_ A sudden tiredness struck him, _'okay, maybe… tomorrow.'_ And with that, Tails fell asleep.

The next thing Tails remembered was waking up to a smell of something cooked. He sat up from the bed, smelling the air around him. It smelled like… cinnamon, with something else mixed into it. He looked on the floor to see a piece of pie on a plate sitting on the carpet next to his bed.

' _Yup, that was the smell,'_ Tails thought as he picked up the pie. He wasn't hungry, but he felt like he would need it for something later. He snapped his fingers and his menu popped up. He place the new pie in his inventory and closed out of the menu. Once the black box closed out and disappeared, he knew he had to tell her. It was time to leave… Slowly, he got up from the bed, fixed the covers to where they looked similar to how they were originally, and walked out of the room. He opened the door and poked his head out of the frame. He looked towards the left hallway, but he didn't see her there. As he turned to the right, something caught his eye. A strange figure was standing in the hallway. It was around a corner, so only a part of its body was showing. He slowly ducked away after Tails noticed him.

"Hey, wait!" Tails cried out as he rushed to chase the figure outside. He noticed the shadow of it go outside of the house, but as soon as he did, there wasn't anybody there. Tails stood at the doorway between the house and the front yard, confused at what he just witnessed. A soft, yellow caught his right eye. Tails faced the source of the light, only to be even more confused than what he already was. There was a small start just sitting there on the leaves. It gave a beckoning presence over Tails. Slowly, Tails began to approach the strange star. He got up to the star, yet it gave off a strange, comforting feeling. Slowly, he raised his arm to touch it, the warmth of it pulsating around his hand as he urged closer. Right as he touched it, a voice could be heard in his head. **Seeing such a small, cute house in the Ruins fills you with DETERMINATION.**

"What? Who are you?" Tails darted his eyes around, trying to find who said that, but nobody was there. He turned back and saw dialogue box appeared in front of him, similar to the one in the menu. The same words that voice had spoken were written on it. Tails read it and felt an urge to continue, whether it was an outside presence or pure curiosity he didn't know. Another text came up, displaying something strange. It showed his name, and the area he was in: Home. In the middle was File… File? Two buttons were present on the bottom; one called Save, and the other Continue. Tails, hesitant at first, clicked "Save". The words glowed yellow and changed to "File saved!" and the box disappeared. Right as it disappeared, a voice startled him.

"My child? Are you alright?"

Tails looked to see Toriel giving a concerned, yet confused glance.

"Miss Toriel, do you see this?" Tails moved out of the way, so he could reveal this to her, but she still gave a confused look.

"I do not understand, what do you mean if I see it? See what?" Toriel question the fox.

"Do you not see this yellow star here?" Tails nearly jaw dropped; Toriel just shook her head.

"Are you feeling alright? Are you hallucinating?" Toriel asked, concerned for the fox.

Tails looked back at the star, thinking about what she said, before sighing, "yeah… I'm good…"

"Come along, small one. My cinnamon-butterscotch pie is ready!" Toriel beckoned the fox. Tails followed her and got a slice of pie, his heart heavy knowing what he has to say next. As they sat at the table, nobody spoke for a few moments before Tails spoke up.

"Miss Toriel, I need to talk to you," Tails requested.

"Yes, my child?" Toriel shot him a confused look.

"I… I wanted to thank you, again, for all that you've done. However, I have to say…" Tails trailed off, sadness in his voice.

Toriel took immediate notice, "my child are you alright?"

"*sniff* Y-Yeah, I'm okay. Miss Toriel, do you remember what I-I said about my enemy, Dr Eggman?" Tails choked.

"W-Well, he's a bad person who harmed innocents and forced you out of your home," Toriel replied, still worried about the fox.

"H-He's holding my best friend hostage, and I need to save him. Eggman is the reason why I'm down here, injured and scarred. If I don't save him now, he and all my friends up at the surface could die, Miss Toriel. DIE!" Tails had a sudden burst of rage come out of his voice, scarring Toriel. He took notice of his irrational behavior, "I-I-I'm so sorry. I just-,"

"No… I understand…" Toriel gave a very serious reply. Tails looked up and saw her face, it was scary, but also submissive and protecting. She continued, "down here in the Ruins, you would not be happy, especially with what you have been through, I will put them aside." Toriel got up from her seat.

"Come," She beckoned Tails to the stairs. Tails slowly got up and followed her, wondering if he did something wrong. "Ahead of us lies the exit to the Ruins, I… will allow you to leave, but promise me…" She trailed off. Tails looked up at her, but she didn't budge, "promise me to never return…"

"WHAT?! But I-," Tails exclaimed, but was cut short by a sudden hug. Tears rolled down the two of their faces as they cried for a moment. Toriel got up, "well, you do have my number. If you wish to call, just do so. I will be here when you need me."

Tails didn't know what to say, he could barely even make a word. He looked up at Toriel and mouthed 'thank you' before moving on. Everything was hurting in his body again, but mostly his soul. It pained of losing a new friend, but something kept him going; and no matter what he was **determined** to rescue his brother from Eggman.

Tails opened the door, to which opened another hallway. He looked back to see Toriel smiling at him, waving at him. He smiled, waved back and pressed on. He looked forward at the hallway, sucked up a deep breath, and walked forward. The hallway was extremely long, given that they were under a mountain. It felt like it went on for ages, until Tails made it to the other side. Another door was present, but when Tails opened it, there was yet another surprise. In the middle of the room, was a familiar golden flower, with an evil grin on his face.

"Well, well, well… if it isn't the two tailed _freak!_ " Flowey laughed.

"H-Hey!" Tails yelled in offense, "w-what do you want?"

"Calm down _friend,_ I wanted to tell you something," Flowey gave a smirk. Before Tails could respond, Flowey cut him off, "no, it's nothing anything _too_ bad, just a friendly gesture! If you want to survive out there, don't let _ANYONE_ see your soul. It might… upset some locals."

"Why are you telling me this?" Tails gave a snarl.

"Like I said before! A friendly gesture! And besides," Flowey's face turned demonic like once again, making Tails fall back in fear, "in this world… _**IT'S KILL, OR BE KILLED!**_ " Flowey gave maniacal laughter before disappearing into the ground. Tails laid on the ground in bewilderment, before shaking the thoughts out his head. He stood up and faced what was before him. An Archway that led to the outside world. Tails pulled all his courage in him, took a deep breath, and walked through it. A light flashed blinded him for a few moments.

Right as the doors closed behind him, the only thought on his head was _'it's so cold!'_ Tails looked around him and saw a snowy forest all around him.

"How does snow, u-under a m-mountain?" Tails complained and shivered slightly. He looked behind him to see the shut door behind him. Tails sighed, seeing his breath in the cold, and faced the path in front of him.

"Well, only w-way is forward," Tails muttered to himself as he walked. The ground was covered in snow, with his shoes crunching the ground beneath him as he walked. Up ahead, he noticed a large stick on the path. There were no others around, so it made him curious as to why it was there. He tried to pick it up, but pain made him stop. There was no way he could lift it in his state. He left it and moved on. _'I hope there's a town up ahead,'_ Tails thought as he pressed on in the cold. All of a sudden, a large snap came from behind him. Tails swerved his head to see that giant stick completely destroyed. Tails' eyes widened in fear as he examined the stick.

' _How can something destroy a stick like that, it must be strong,'_ Tails thought to himself. His heart began to race. He didn't want to encounter this thing if that thing could destroy a stick like that; Tails just hoped it wasn't an enemy. Tails continued on, going faster down the path. Surprisingly, sweat was beginning to form on his face, even though he was in snowy weather. Tails heard a sound that made him jump out of his skin. Snowy footsteps echoed behind him, really close, too. Tails darted his head, but no one was there behind him. Tails picked up the pace, and ran as fast as his injured body could take him.

' _Oh God, I hope that isn't Flowey messing with me!'_ Tails' voice screamed in his head. Tails kept running until he couldn't. He was tired from running, and stopped for a moment to catch his breath. When he looked up, he saw a gateway on top of a wooden bridge.

' _Is this suppose to stop anybody, or-?'_ Tails pondered, but stopped when he heard the sounds of footsteps behind him again. His body froze in terror as the footsteps came closer and closer. He felt his sins of the past crawling down his back as the entity came closer to him. It stopped right behind, Tails could feel it behind him.

" e. D o n ' l? d, d." A dark voice said behind him; and here he thought his presence was terrifying enough, now add this voice and boom! instant nightmare! Tails knew he couldn't outrun or outmatch this guy, so he decided to accept fate. Slowly, he turned around to face the creature behind him. It was covered in shadows, but it had it's hand raised out. Tails took a deep breath in, closed his eyes, and reached out to shake it's hand…

There we go, chapter 5 done! Sorry for the small chapter, I'm not in the best condition right now. I feel like I can't take anything anymore at this point, but I know suicide won't solve it. Besides, who's gonna write these stories still :D

Next thing I post is Chp 3 of Legend of Spyro: Dragonriders' Destiny.

 **THANKS FOR READING! PLEASE R &R SO I CAN BECOME A BETTER WRITER FOR ALL! :D**


	6. Chapter 6: Course of Action

Not much to say other than my usual rant about my hatred to school and everything.

Also, after this and Legend of Spyro: Dragonrider's Destiny are finished, I'm probably gonna do one series at a time to keep myself forward and less stressed about multiple plots. I already have a cool story, but waiting after I finish these to enact it!

I hope you like this chapter a _skele-ton,_ because this chapter is gonna get _humerus_! ;)

Out of all the sounds in the world, this was one Tails didn't expect to hear. The sound of a whoopee cushion filled the silence around them as he shook hands with the figure. Ironically, as that happened, the shadows that encompassed him were lifted, and Tails could see who it was, only to question his very existence. It was a skeleton shaking his hand; it creeped him out, but he did expect something far more sinister to reach out and grab him. That gave a bit of relief, but at the same time, just as freaky. The skeleton wore a blue jacket with a white shirt underneath. He had black shorts with a long strip down the sides of it. It wore mittens, one of which had a whoopee cushion wrapped around it, as well as white slippers. Tails could see white dots that made up it's eyes, kinda creepy, too. It was smiling, a rather… happy one?

It was laughing, but not at him, "heheheh, the old whoopee cushion in the hand trick. it's always funny!" It didn't move it's jaws when it talked, how could it talk if it can't - ...it was probably monster magic…

"Ah, heh… heh… yeah," Tails try to laugh, but was too freaked out to say anything. He looked away, slightly, but gave a fake smile.

"aw, c'mon kid, you have to admit. it was _humerus_ to see your reaction," the skeleton quipped. Tails was silent for a moment, processed what the skeleton said. He gave a giggle, while covering his mouth.

"anyway, your that 'person' the lady behind the door was talking about right? that's cool. i'm sans. sans the skeleton," Sans said, giving a glance to where he just came from.

"Oh, you mea-?"

"listen, if i was her, i wouldn't let anybody know who i am. i'm sure that's exactly what she would want, too," sans gave a serious look.

"Probably," Tails thought about what he said and agreed.

"now, cmon. go through this gate thingy here. my brother made these bars way too wide to stop anybody. actually, i think that him over there," Sans pointed forward. Tails looked ahead and gave a nervous glance.

"relax, he's harmless. despite his appearance and everything," Sans reassured him. Tails nodded and walked forward. He saw a lamp, and a concession stand.

Sans was about to say his 'behind the lamp!' but he wasn't human. He might not need the lamp.

"SANS!" A voice startled him out of his trance. He looked up to see Papyrus standing in front of him. He looked upset at something, probably the puzzles.

"sup bro," Sans winked. Tails noticed this and just looked baffled.

"SANS! IT HAS BEEN 8 DAYS SINCE YOU'VE-," he noticed Tails, who kinda shrunk in fear, "OH! DID YOU MAKE A NEW FRIEND?"

"huh? oh yeah! paps, this is tails; tails, this is my brother papyrus," Sans introduced each other.

"H-Hi," Tails gave a small, nervous wave.

"HELLO, TAILS! I AM THE GREAT PAPYRUS! BUT PAPYRUS WORKS, TOO!" Papyrus waved back, "ANYWAY SANS! I WILL DEAL WITH YOU LATER, RIGHT NOW! I MUST MAKE MY FAMOUS SPAGHETTI FOR OUR NEW FRIEND! NYEH HEH HEH HEH!" He scurried off, back the way he came from.

Tails looked excited for the spaghetti, but Sans stopped him, "by the way, he's not a good cook. he can barely make something edible." This kind of discouraged Tails for the future.

"now, let's get straight to the point." Sans walked in front of Tails. He turned around and faced him with a serious expression, "i understand you have a lot of questions. since you probably don't understand a whole lot, i'll be nice and answer all i can for you. now what's on your mind?"

"Well, its like this…" For the next ten to twenty minutes, Tails explained everything that happened to him in the past year up to now.

"i see…" Sans listened as the fox finished. "want my best advice? don't let anybody know about your soul, keep away from monsters that might seem harmful and you will be fine."

"Okay?" Tails responded with more of question.

"Follow me, kid," Sans gestured forward. They past his sentry station up to a box. Tails noticed something yellow again, it's that weird star again!

"Hey, Sans?" Tails called out, the skeleton turned around.

"Are there supposed to be these weird, yellow stars everywhere, or is that just me?" Tails pointed to the star. He didn't say anything. Tails just stared at the skeleton. Sans' eyes were gone, and replaced with dark pits. It looked terrifying, but he looked terrified about something, too.

"quickly, with me!" Sans looked around.

"W-What? What's wrong?" Tails asked, but got only a panicked looks from the skeleton. Suddenly, everything went dark for a millisecond, and back. Tails was mixed with different feelings: nausea, dizziness, all those; it was as if he got off a carnival ride. He looked around to see they were in some sort of room that looked like a laboratory. There were blueprints on the wall, each with symbols written on them. He noticed Sans staring at him, as of judging him for something. There was something under a tarp behind him, but Sans was the main focus.

"H-How did-," Tails tried to speak, but nearly fell over in dizziness.

"listen kid… you need to hear this," Sans' voice was deep, it felt darker, too, "it's about those "yellow stars"."

"What? What is it? What are they?" Tails cried out in desperation.

Sans just glared, then looked down, just before Tails' feet, "you… are holding a power; and it's the power… of DETERMINATION…"

 _Time jump back to Tails' "death"..._

Sonic stared at the mountain where he lost his brother. It was getting smaller and smaller out of view as he was taken away. He looked at the cuffs and claw that were holding him. He knew he couldn't struggle, there was no point to do so. Slowly, he looked up towards his captor, Eggman. He wanted to be angry, he _should_ be angry, but so much grief was in his heart. He saw Eggman cackle and press a button. Sonic heard a sound from his right. There was nothing at first, but something flickered. In an instant, the red hull of a ship filled the area, making Sonic more scared than he already was. It was the Egg-Carrier, Eggman's prize ship. The Egg-pod slowly flew towards the top, where the landing deck could be seen. There were hundreds of robots on top, waiting for them to land.

Sonic gulped as the pod touched down on the metal surface. The robots swarmed the pod, but staying at a close distance around them. Sonic noticed one had a launcher of some sorts, but he didn't know what it was. All of a sudden, it fired at him. A large shock hit him, causing him so seize up in pain. The claw let go of him and he fell to the ground. Bolts of electricity still surged around him as he laid on the ground. Eggman got our if the pod and walked over him, his shadow encompassing over Sonic.

"Now I have won!" Eggman smirked as he laughed a maniacal laugh. Sonic watched the world around him fade to black, and the darkness consumed him.

Eggman saw he was unconscious, "take him to cell C-49, he will have a good time there…" Eggman chuckled. Now to the next step, obtain the remaining emeralds from Team Sonic. He walked into the ship, passing through the hallway of metal surrounding him. Any nearby robots who noticed him in the hallway saluted before returning to duty.

' _At least they know their place,'_ Eggman thought as he walked. He stopped and faced a door that read "central communications hub". He opened the door and went inside. He saw a central terminal, with monitors and circuitry everywhere. He approached a chair, and sat in it. He knew how to get those emeralds, and one way or another, he will win. Perhaps he could "negotiate" Sonic for the emeralds? That idea filled him with evil as he flicked on a few switches. A sound filled the room as the hum of the computer came to life. A monitor turned on, a small icon at the top read "rec".

Eggman coughed, clearing his throat. He took a deep breath and spoke, "attention all members of Team Sonic."

Before you go off saying "THIS CHAPTER SUCKS!" and "WHY IS THIS ONE SUPER SHORT!" Undertails is starting to become like a small side project to me now. I still love making it, but it might not be as frequently as before. I personally feel better with completing my Legend of Spyro crossover first than this.

Is this out on hold? Probably. If I have a _lot_ of time, yes I will continue to produce Undertails with the same quality as usual, maybe better or worse. Like I said, my main focus is shifting and I want to make that **SUPER CLEAR**!

Truth is: I'm not as happy as I once was, this has helped me. It's better for me to do this than to leave it **all** in the dust, just one or two things.

With that said, I still love creating this series, but don't expect super frequent updates, but one maybe every other week, okay? I'm really sorry for any inconvenience.


	7. Chapter 7: Meanwhile PT 1

Now, we shall know the rest of Team Sonic's side of the story.

Note: I am more focused on my 2nd book: Dragonriders Destiny, than anything, so I do apologize for the lack of quality of time of updates on these.

Also! A part of me wants to make a series I had planned for a _long…_ time, but at the same time… I'm not sure on how to proceed with it anymore. I don't know if I should start it or whether I shouldn't.

Anyway, to the quick chapter!

 _Back at the Thorndike Mansion…_

The entire lot was filled with noise as the names of Sonic and Tails were called. They checked everywhere and called their names out to find them around the mansion, but nobody came. After minutes of valiant searching, everyone bacame nervous about the duo, and met up near in the living room.

"Where could they have gone?" Amy asked, but she knew that question had no meaning at the moment since no one knows where they are.

"Not sure, but if you ask me, they probably are doing a race like they've done in the past or something," Knuckles shook his hands as he replied. Everyone just looked around and nodded, knowing he was probably right. Just then, Chuck and Chris came running through the front door.

"The X-Tornado is gone!" Chris yelled. Everyone looked at Chris, more panicked about their dramatic entrance than the topic.

"Maybe they did go out?" Cream said, her Chao danced around her head.

"That would explain everything, but why didn't they leave us a tip or something that they had left!" Amy was frustrated. Before anybody could respond, the TV monitor suddenly turned on, diverting everyone' attention to it. That shouldn't have happened. Chuck stared into the monitor, it didn't add up. The only times that it should turn on like this was because of a thunderstorm or… no…

As if fate read his mind, the monitor revealed a man with a mustache, laughing evilly. Everyone gasped in shock and all simultaneously said, "EGGMAN?!"

"Attention all members of Team Sonic. I believe I am holding something of interest to you…"

"Eggman! How did you-" Amy nearly screamed, but Chris stopped her.

"He can't hear you, Amy," Chris halted her from probably destroying the TV.

"-I believe you value a lot!" The message continued. As he said this, a picture of an injured Sonic appeared in chains, arms and legs spread out. All gasped at the sight.

"Oh! I also have Tails, but you really don't want to see how he's looking," Eggman laughed evilly, "If you want them alive, then you will have to bring me ALL your Chaos Emeralds!" An image of a nearby hillside appeared on the monitor, "meet me here so we can… trade. Oh, and don't try anything funny; one false move… and I'll kill them both. Meet me in 2 hours, or else…" and the monitor cut out and faded to black.

Eggman turned off the monitor and smirked, twirling his mustache. He got up off his chair and walked out of the hub. He walked down the hallway and entered an elevator. As the doors closed behind him, he pressed a button, and the elevator began to go down. He watched as robots passed the window, until he found what he was seeking. A water filled tank came into view, with a cell in the middle. As the elevator touched down, a hallway within the water appeared. The doors opened and he walked through the hallway. As he got towards the front of the cage, he found a chain-bound Sonic, breathing heavily.

"Your friends bought it, and the Chaos Emeralds will belong to me!" Eggman laughed maniacally as he left.

Sonic watched in horror as he left. If he hurt them like he did Tails…

Anger filled his soul as his pupils disappeared. His fur started to glow dark black, and rage began to consume him.

" _I will make you pay…_ "

Short chapter, I know. Had to because of problems with school at the moment.


	8. Chapter 8: Meanwhile PT 2

Okay… I know the last chapter was kinda small (and this one will be, too), I'm not as passionate about this series as I once was, though I still want to make and produce it.

With that said, I should probably shut up and let you read, lol.

 _2 hours later…_

Everyone watched as Eggman's massive Egg Carrier suddenly appear from thin air, scaring the team. The massive ship slowly descended towards them, then halted.

"Well, well, well… think you could escape the planet without my knowledge? I think not," Eggman cackled.

"GIVE US OUR FRIENDS BACK!" Chris screamed, shocking everyone by his violent outburst.

"I will, but first…" There was a pause, before a sound erupted above them. Everyone looked up to see numerous objects along down towards them. They all landed with a thud. Numerous robots, seen and never seen before surrounded them, there was nowhere to run…

"Look!" Knuckles pointed to the sky. Everyone saw a pod land in front of them. As it landed, Eggman walked out with an evil smile on his face.

"Now then, the emeralds…" Eggman held out his hand, to where they can give the emeralds.

"Show is our friend!" Chris yelled, anger filling his eyes. Eggman snapped his fingers, and a smaller ship appeared. It's door opened up, and revealed a chained Sonic.

"Where Tails?!" Amy asked violently.

"In a ship to better suit his care, now _the emeralds…_ " he emphasized.

"No way! Not until you show us Tails!"

Eggman hesitated, but didn't show it, "I'm sorry, but he's better where he is now! You have my word! He isn't harmed!"

"We want to see him!"

"Hand me the emeralds…" Eggman persisted.

"No way in hell!" Chris shouted.

Eggman sighed, "a shame, really. We could've sorted this out peacefully…"

"What are you talking about?" Knuckles nearly hit a robot, which caused all of them to arm themselves. Eggman held a hand up to make them hold their fire.

"You see, I planted a bomb within that ship. If you try and rescue him, it will detonate. Hand me the emeralds, and I will disarm them. Now, the emeralds," Eggman gave his lecture. No one moved an inch. Eggman held a detonator in his hand.

"One…" Eggman opened the capsule holding the switch.

"Two…" He placed his hand on the trigger switch. All the heroes started sweating.

As soon as he was about to flip the switch, an explosion of darkness erupted from the ship behind him. Everyone turned to face what caused the explosion. Team Sonic became scared instantly, while Eggman remained puzzled to how that might've happened. As the smoke cleared, a black hedgehog emerged. His pupils missing, but his eyes were full of anger.

"Three," the hedgehog said, and blasted at high speeds towards the robots below. He came at them, destroying the robots while barely making any contact. The robots fired at the dark hedgehog, but they had no effect against him. The remaining robots retreated back towards Eggman and flew off.

Eggman watched his forces fly back towards the carrier, then glanced back towards the team, "You haven't seen the last of me!" And with that he flew back up towards the Egg Carrier.

The hedgehog touched down on the ground, facing the team. Instantly, he reverted back to his blue self, revealing himself to his team. As that happened, the carrier made a 180% turn, while going invisible.

"SONIC!" Everyone jumped at him and gave him a hug, but he didn't move. His eyes looked dark still. Chris noticed this immediately.

"Sonic… what's wrong?" Chris asked. Sonic began to tear up, hanging his head.

"it's… tails…" Sonic croaked.

"What about him?" Amy approached his side, putting a hand on his shoulder.

All of a sudden, Sonic raised his head up into the sky and said something that would haunt their souls for the rest of their lives, "tails…. he... HE'S DEAD!"

This chapter was designed to be small due to a more of Tails' perspective of this adventure.

Plus, other things has gotten itself stuck in my schedule, lol.


	9. Chapter 9: fast travel

Hey, everyone!

I'd recommend you check out my second FF! Legend of Spyro: Dragonriders' Destiny! For those who love godly dragons and dragonriders, this is perfect for you! It's a lot better than my works here! I'll leave a link to the first chapter here:  s/13177263/1/Legend-of-Spyro-Dragonriders-Destiny.

This might be a combination of smaller chapters, too. Just so I can finish this and move on to future projects.

* * *

"Determination? I don't understand," Tails held a puzzled look. He may have an IQ of 300, but this was far beyond anything he knows. A part of him was excited to learn this new knowledge, as another felt fearful.

"well, lemme put this into context for you to understand. imagine if you had the ability to undo your mistakes in the past. you're able to set a certain point in time as a "save point" and be able to continuously come back. every time you do it, the people won't remember everything, but it might come back as a 'deja vu' feeling," Sans attempted to make it easier for Tails to understand.

"Then how do you know that? Do you remember everything?" Tails asked. That part made sense to him, but Sans' connection to all of this didn't.

He just shrugged, "i've studied for a long time and lived through it countless times. i basically know everything thing."

"How come you're the only one that remembers?" Tails asked again. Sans just shrugged, he was kinda like Sonic, but lazier in every way.

"Will any monsters try and fight me?" Tails started to get nervous.

"doubtful. they may ask where you came from, but otherwise shouldn't attack you unless you did something against them," Sans tried to calm the fox down a bit. Tails gave a small sigh.

"Hey, could you teach me a little more about the FIGHTing mechanic? I'm still not very use to it," Even though Toriel helped him out, it's best to know more about something than to walk through it blindly.

"sure, kid. ready?" All of a sudden, the room grew into a black box, with Tails' soul popping out. Sans was black and white, since every color pretty much changed.

" _Song that might play when you fight sans" chimes in..._

"alright, kid. what do you want to know?" Sans stood there with his hands in his pockets.

"Well, the basics is all I need right now," Tails smiled as he gave a nervous laugh. Sans just shrugged.

"ACT allows you to to… actions in battle. go ahead and check me," Sans told Tails as he clicked the ACT button, then pressed 'Check'. The box below read, "Sans: 1 ATK 1 DEF. The easiest enemy. Can only deal 1 damage."

"Huh, with these stats, I can see why your so laid back," Tails tried to make a joke.

"ehh... that's one of the reasons," Sans shrugged back. Man he really is more like Sonic.

"Okay what now, again?" Tails got into a defensive stance.

"normally, i would attack, but since this is more of like a tutorial, i forfeit my attack," Sans said as the dialogue box appeared in front of Tails once again.

"Actually… I think I'm good with this for now," Tails didn't want to hurt him after seeing his stats. Sans shrugged once again.

"ok, just spare me and this will end." Tails clicked the mercy box, and clicked spare. The battle ended and everything returned to normal.

 _Music ends..._

"Hey, Sans. How come you only have one of well… everything in your stats?" Tails asked. Sans kind of looked away, before looking back at the fox.

"well... not entirely sure, guess it's all just 'one in the same'', Sans winked. Tails giggled at the pun, as he followed Sans out of the room.

Papyrus waited for the fox and his brother to meet with him at the first puzzle. Papyrus began to wonder where his brother went.

' _AH, HE'S PROBABLY SLEEPING AT HIS POST AGAIN. I SWEAR, IF I HAVE TO-,'_ his train of thought was broken as his phone began to ring. Pulling his cell phone seemingly out of nowhere, he looked to see his caller was; surprisingly, it was Sans. He answered it with a "BROTHER! WHERE ARE YOU?"

"at our house. tails said he was shivering so i took him inside," Sans' voice came through.

"OH! OKAY, WELL… THAT WAS A SURPRISE! I WILL BE RIGHT OVER!" Papyrus spoke as he hung up the phone.

"paps, you don't have to-," sans heard a static noise, he looked down to see Papyrus had hung up the phone.

"What's wrong?" Tails asked.

"oh, my bro is coming here. don't worry, he's harmless, even though he tries to look like he's not," Sans reassured Tails.

"Oh! Okay." Approximately one minute later, surprising Tails slightly, Papyrus opened the front door.

"HEY, SANS! I'M HOME!" Papyrus' voice echoed the home.

"hey, bro." Papyrus noticed Tails sitting on the couch.

"ARE YOU ALRIGHT, MR. TAILS?" Papyrus asked.

Tails chuckled. A part of Papyrus reminded him of Cream in a way, "yeah, I'm fine. And please, just call me Tails."

"OH! OF COURSE!" Papyrus spoke. Papyrus noticed Sans grabbing an unopened ketchup bottle from the fridge.

"HONESTLY, SANS! ONE OF THESE DAYS YOU'RE GONNA STAIN YOUR CLOTHES, AND THEY WILL BE RUINED FOREVER!" Papyrus scolded him. Tails watched Sans chug down a quarter of the ketchup bottle. Tails froze in pure shock, HOW CAN HE EAT OR DRINK ANYTHING IF HIS MOUTH DOESN'T OPEN EVEN ONCE!

"it's fine bro. besides, i still have a spare geto in my closet," Sans shrugged it off. A thought reached his lazy mind, "hey, don't you think you should go report to undyne?"

Papyrus' face lit up, "YOUR RIGHT! MAYBE YOU SHOULD COME ALONG, TOO, TAILS!"

Tails began to look nervous and looked at Sans, "w-who's this 'Undyne?'"

"the captain of the royal guard. she's a strong leader, very determined, too. she may be… unique, but she's cool once you get to know her," Sans said.

"I'LL BE UP AHEAD, JUST TAKE A LEFT AFTER YOU LEAVE THE FRONT DOOR, AND I MEET YOU THERE! NYEH HEH HEH HEH!" Papyrus cackled as he ran out the door. Tails noted he had a lot of energy compared to his brother. Huh… now that he thought about it, they are literally polar opposites in almost every way… who would've thought.

"Should I go?" Tails began to sweat lightly.

"as long as she doesn't see you soul, you'll be fine. she is a bit destructive, though. i advise caution. don't worry, i'll be up a head," Sans reassured him.

"Okay, thanks, Sans," Tails smiled.

"don't mention it, kid," Sans winked back. Tails exited the warm house and returned to the snowy town around. He took a left turn and walked down the path. He noticed the river next to him was surprisingly flowing and not frozen over. He saw Papyrus standing in front of him, waving for him to come over.

"HELLO, TAILS! ARE YOU READY TO MEET UNDYNE?" Papyrus asked.

"Uhh… sure," Tails replied.

"SPLENDID! FOLLOW ME!" Papyrus said. The two walked up a path that diverted from the main road. The are slowly turned from a frozen ground to a musky, swamp-like area. The sudden change of terrain made Tails ponder about the Underground as they pressed on. They pressed on to a ridgeline, where towards the right of it was a tall grass area.

"HELLO, UNDYNE!" Papyrus cried ahead towards a darkness. Tails looked to see where or who he was talking to and didn't see anyone at first, but he was quickly mistaken. A tall, grey armored figure emerged from the darkness. Her armor was very bulky, this was probably Undyne.

"Hey, Papyrus. Got anything to report?" A voice came through the helmeted warrior. It's sounded rough, one of the perks to being a military leader Tails supposed.

"NOTHING TO REPORT CAPTAIN! ALSO, I MADE A NEW FRIEND TODAY! I THINK YOU WILL LIKE HIM!" Papyrus exclaimed. The warrior looked down towards Tails. She took off her helmet to reveal a one eyed fish lady. Her sharp teeth in some sort of smile. She had blue scales an eyepatch covering her left eye.

"Nice to meet ya, what's your name punk?" She asked, kneeling to where she was about his height, but even then she was still taller.

"U-Uhh.. T-Tails, ma'am!" Tails tried to be respectful with a military like tone, but his nervousness got the better of him. She howled with laughter.

"Ahh, relax, squirt. I'm not gonna hurt you! If Papyrus likes you enough to be his friend in pretty much an instant, then your cool to me. Please, you can just call me Undyne," She reached out a gloved hand. Tails reached out to shake it. When she shook his hand, he felt like he was gonna lose his arm to just her grip alone.

Undyne noticed something, "come to think of it, I've never seen a monster like you before, where are you from?"

"U-U-Uhh… y'know, around here, heh…" Tails laughed nervously. Undyne held a slight glare, but dropped it as he was probably intimidated by her… a lot.

"Heh, well, I'm off to Alphys. Hey, why don't you come along? She's like, super awesome and nerdy!" Undyne laughed. Tailed perked up at this. _Another scientist who might be able to help me out!_

"Yeah, okay! I have nothing better to do, so-!" Tails was interrupted by Undyne picking up the small fox. She placed him on her back, giving him a piggyback ride.

"Don't worry, Papyrus! He's safe with me! We'll meet later for our one-on-one training!" Undyne called out before zooming to Hotland. Papyrus was waving as they left.

"huh, i guess that's one way to make friends," Sans said. Papyrus immediately faced him stood in shock.

"SANS HOW LONG WERE YOU STANDING THERE?!" Papyrus exclaimed.

"long enough," was all he could say.

As the two ran at surprisingly immense speeds, given the fact that Undyne was wearing her armor while she ran, a thought ran into his mind. What did she mean by 'one-on-one training'?

"Hey, Undyne. May I ask you a question?" Tails asked.

"Sure, punk! What's up?" Undyne looked back slightly to see him while she ran.

"What exactly did you mean with Papyrus and his 'one-on-one training'?" Tails continued as they ran through certain parts of Waterfall.

Undyne sighed, "Papyrus wants to join the Royal Guard."

"That's so cool!" Tails cheered.

"Yeah, but here's the thing," Undyne continued, "he's just too innocent. I'm afraid if I send him out there, he would get himself hurt or killed, and that is something I don't want for the both of us. So, uh, I decided to teach him one on one! Also to cook, but truth be told, we kinda suck!" She laughed a little. Man a lot of people here reminded him of his friends on the surface.

"I understand," Tails said.

"Anything else on your mind, kid?" Undyne asked as she jumped over a small pit.

"Yeah, actually. Where exactly are we going?"

"Alphys' lab. She's the Royal Scientist of King Asgore! She's such a nerd!" Undyne said as they ran across a bridge.

"Oh…" was all Tals could muster.

As they passed the Undyne encounter area (when not doing genocide route), Tails noticed a star on the ground, but they ran by it before he could say anything. They passed through a passage and sign that said "WELCOME TO HOTLAND!". Tails wanted to try something. He moved his tails around to see if they are healed enough. He got a much better response from them, but they still hurt. Probably not a good time to fly, but at least they are healing. Tails noticed the area grow redder and more heated. Tails looked forward to see a bridge up ahead with a magma pit underneath. Tails began to worry, no wonder why it was called 'Hotland'. They passed by a sentry station, similar to Sans'. Surprisingly, it has snow on its roof, making Tails wonder how it wasn't melting. They crossed the bridge, where a water fountain was stationed up ahead. Tails noticed Undyne began to look heated as she began to sweat.

"Alright, punk. I'm gonna have to put back on the ground and get a sip of water. Sorry, it just that my armor gets extremely hot when I run like that to Hotland," Undyne explained as she lowered Tails so he could hop off her back.

"It's fine!" Tails shook it off, but decided to grab a sip of water after her. He had fur, so he was kinda having the same problem as her. As he was drinking the surprisingly cold water, he noticed Undyne calling someone on a phone.

"Hey Al! I'm coming over and I have someone you might wanna meet! Sounds cool! See you there!" Undyne hung up the phone, Tails assumed it was this Alphys he had heard of.

"Hey, where exactly are you from?" Undyne eyed him suspiciously while they continued.

"U-Uh… Undyne… I… honestly don't like to bring it up. It hurts everytime I talk about it," Tails lied.

"Oh, uhh… okay. Sorry, just curious," Undyne looked away. When the they approached the lab, the first thing that Tails noticed that the wall had a giant sign the says "LAB" on it, descriptive…

Undyne walked to the front door, but Tails saw another star in front of it. Tails was about to ask Undyne, but that might make her suspicious, and seeing as she was a military leader it's best to not cause a disturbance. Tails quickly set his point and closed the menu.

"Hey, are you just gonna stand there or are you coming?!" Undyne shouted, startling the young fox.

"Y-Yeah!" Tails hurried along until he stood next to Undyne. She knocked, or rather, banged on the door three times. Each strike sounded like an earthquake. Undyne moved away from the door slightly.

"I'd like you to meet… Dr. Alphys!" Undyne shouted as the doors opened up, revealing a small lizard like monster in a white lab coat.

* * *

I apologize for the time gap, just focused on other things in life.

Please R&R, and have a nice day :D


	10. An Apology to All

Hi, everyone…

I have new for Undertails…

This project is now considered "ON HIATUS". I have no further intentions at the moment to continue on this series.

Why!? You might ask… well… I realised when creating my second Story that I had more of a passion for it, and as time grew on and it grew, this one felt more of a old hanging lantern. I didn't feel as fired up about this series as I thought. Eventually, I grew tired of it.

I'm sorry about all of this, I just want to get to my future stories I'm anxious to make! Please forgive me, I really didn't want to do this, but at this point… I… just had to…

If all goes well in the future, I might come back and remaster this, but no guarantees...

If you wish to follow my other stories here they are:

Legend of Spyro: Dragonriders' Destiny: s/13177263/1/Legend-of-Spyro-Dragonriders-Destiny

Sonic Boom: Temporal Troubles: Not out yet


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